Metallic alloy



letented Apr. l 3.5326.

STATES PATENT OFFICE.

TEQZi'IXl-E P. SHIELDS, 035 NEW YGRK, N. Y., ASSIGNOR TO SHIELD & MQORE,A FIRM CQNSEQTHTG OI" TEOEAE Ti. SHIELDS AND A. MOORE, OF NEW YORK, N.Y.

METALLIC ALLOY.

Ito Brewing.

To all whom may concern:

tie it known that I THOMAS P. Sinmns a i 1r itizen of the Bolted btetes,residing at New York Git New York have invented certain tionwith-several. specific examples but it is 15 to he understood that theinvention is not restricted to these specific examples.

In s first example, I employ about 58.3% of fine golo, silver, 13% ofzinc and 25.2 2 of copper. This produces an alloy which is relativelylow in gold, but possesses the property of not readily tarnishing, andthis alloy will be found to have the desired green gold color, and. willhave good working properies. lhis alloy is very cheap to produce, andcan be readily worked. with ordinary goldsmiths tools, and also can bereadily enameled.

In this example, as in several of the other 30 examples, the amount ofsilver can be great-- end if desired can be omitted ly reduced,

and if it 18 desired, to decrease altogether, the amount silver, creasethe amount 0t chromium proportionand an alloy to form a good substitutefor old, from which silver is entirely absent, would contain about 8% ofchr0- mium as a minimum. I

in another particular example, i0% of w {tine gold, of chromium, 30 ofcopper, 20% of zinc and no silver are employed. In this alloy it isnotedthat the amount of gold is relatively low so that the alloy is cheaplyproduced, and is very suitable for making up jewelry.

The proportions 7 1 oi. cnromiuni, 2% of tiuc' it is preferable to intheconstituents can Application sacs May 20, 1925. Bass No. 31,671.

be varied substantially, and the following table illustrates in ageneral Way the amount of variation which csnbe had, While still givingvery satisfactory products Percent. Gold 4012060 Copper 24m Zinc 10 to30 Silver 0 to 15 Chromium i 1 to 10 In making up the alloy, Ipreferably mix together the chromium, copper and zinc (and silver if itis-to be used) in the proportion in which they are toaexist in the finalalloy. These'metals can be mixed together, melted and granulated, toform a. stock alloy, and the desired amount of this is added to thedesired amount of fine gold, to give the percentage of gold desired, andagain melted and stirred, to give the desired tine product.

The final alloys, as will be noted, do not contain any of the ,metals ofthe platinum group, which have heretofore been used in alloys of thisgeneral class, for the prevention of tarnishing. The metals of thisgroup however are extremely expensive, and l find that the alloysproduced in accord ance with the present invention arqisubstan tiallyfree from tendency to tarnish, even in the form of jewelry about 10tov14 carat.

The final alloy can of course contain smell and somewhat immaterialamounts of other substances, which do not materially alter theproperties of the final alloy. Thus, in commercial practice, usingmetals of commercial qualities, some minor amounts of" impurities may beintroduced.

1 claim v 1. An intermediate alloy consisting of 1 to 10 parts ofchromium, 24 to ports of eoppcn lO to 30 purts of zinc, together withsome silver but not substantially above 15 parts thereof. 4 2. Anintermediate alloy consisting esseni ially of 8 to 10 parts of chromium,24 to *ter together amounting to at least 8% of 50 parts of copper, and10 to 13 parts of the total alloy. zinc. 4;. A gold alloy consistingessentially of 3. A gold alloy "consisting of 40 to 60% 4:0 to 60% ofgold, 8 to 10% of chromium,

efgold, 24110 30% of Copper, to 30% of to of copper, and 10 to 30%o'fzinc. zinc, 1 to 10% ofchmmium, and some silver, In testimony whereofI aflix my signature. but not more than 15% thereof, the two lat- ITHOMAS P. SHIELDS.

